Replace Mint with Ubuntu in dual booting system
Solution 1:
If you want to use the Mint partitions (this will ERASE Mint), in the screen that you described in your question you have to select the option "Something Else", then:
- Select the ext4 partition
- Set the mount point to
/ - Flag the
format the partitionoption
If my memory assist me good enough the swap area is auto-detected.
In the something else screen you have a mini-gParted during the installation, so pay attention on what you're doing.